where the hell have they all gone to?

I was looking for another set and I can find ALOT of player but less than 15% of the results are missing the discs
and the seller says "works 100%" and a lot along the same lines and I wonder, how the hell do they know if they don't have the disc then its pretty much useless and untestable!

any way I was wondering because I was aiming to get some of the colored Japanese game boy players and I figured it would be cheaper to get a cheap set with the disc to make it work but apparently not.
also aiming to get a very pimped out gamecube set. I cant find 2 of my 5 wave bird controllers and I still haven't found any component cables at a good price